Monodisperse alginate hydrogel microbeads for cell encapsulation

This Communication describes the production of monodisperse alginate hydrogel microbeads (94-150 mu m) using a method that combines internal gelation method with T-junction droplet formation in microfluidic devices. The use of calcium carbonate (CaCO3) nano-particles allows internal gelation method to be applied to micro-scale production for the first time, and microfluidic devices allow us to produce microbeads with narrow size distributions. Our approach not only allows easy control over bead size by varying flow parameters, but also allows better monodispersity and control over the shape of the hydrogel beads compared to conventional external gelation methods performed in microfluidic devices. Both blank and cell encapsulating alginate hydrogel beads of various shapes were successfully produced using this approach in non-silanized/silanized poly (dimethylsiloxane) (PDMS) devices. Also, we demonstrated that the gelation conditions in our approach were mild enough to encapsulate mammalian cells (Jurkat) without loss of their viability, and studied the effect on cell viability with varying concentrations of CaCO3.